A variety of guns using discharged compressed gas for firing relatively fragile projectiles are known employing manual, semi-automatic, and fully automatic arrangements. Compressed gas powered guns are typically useful as pellet marking guns, commonly called paint ball guns. Paint ball guns have attained widespread use in a recreational sport known as paint ball or war games. Typically located in open spaces with varying types of terrain, opposing sides employ guerilla-type strategy to seek out and "kill" one another by marking the opposition with a paint ball which is fired from a gun and bursts on impact.
Paint ball guns use compressed gas to fire a gelatinous capsule containing a marking material. The marking capsules (paint balls) typically enclose a mixture of water and vegetable coloring so they are not toxic and can be removed from clothing and other surfaces with simple water washing. The capsule breaks on impact with the target dispersing the material to mark the target, for example an opposing player, where hit by the capsule. However, the marking capsule must have sufficient rigidity to avoid breakage during loading and fire operations of the gun.
In U.S. Pat. No. 5,280,778 (Kotsiopoulos) a compressed gas powered gun is disclosed having a semi-automatic firing mechanism for enabling successive firing sequences. The firing mechanism includes a sear having a latch arm, with a cam at one end and an interlocking element at the other end. The cam is positioned to close a firing chamber as the latch arm is rotated. The interlocking element is positioned to concomitantly release an actuating bolt as the latch arm is rotated. A recoil spring repositions the actuating bolt for engagement with the interlocking element upon discharge of the firing chamber.
Operation of the trigger of this gun first releases the hammer to fire a paint ball and subsequently switches a valve to re-cock the gun. Thus correct operation requires these two stages to achieve correct operation of the trigger. The timing of these two stages is also dependent upon the speed of trigger operation.